Biscitraconimide (MBMI)/Polyetherimide (PEI)/CSA doped PANI nanocomposite films were successfully prepared by in-situ polymerization method. The obtained nanocomposites possess higher thermal stability than neat MBMI/PEI semi-IPN matrix. With increasing wt% of CSA doped PANI nanoparticles, the decomposition temperature of MBMI/PEI semi-IPN increased. Structural studies were done by Fourier Transform Infrared (FTIR) Spectroscopy.